mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Core\Logger;
   6 use Friendica\Core\System;
   7 use Friendica\Database\DBA;
   8 use Friendica\Model\PushSubscriber;
   9 use Friendica\Util\Network;
  10 use Friendica\Util\Strings;
  11
  12 function post_var($name) {
  13         return !empty($_POST[$name]) ? Strings::escapeTags(trim($_POST[$name])) : '';
  14 }
  15
  16 function pubsubhubbub_init(App $a) {
  17         // PuSH subscription must be considered "public" so just block it
  18         // if public access isn't enabled.
  19         if (Config::get('system', 'block_public')) {
  20                 System::httpExit(403);
  21         }
  22
  23         // Subscription request from subscriber
  24         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  25         // Example from GNU Social:
  26         // [hub_mode] => subscribe
  27         // [hub_callback] => http://status.local/main/push/callback/1
  28         // [hub_verify] => sync
  29         // [hub_verify_token] => af11...
  30         // [hub_secret] => af11...
  31         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  32
  33         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  34                 $hub_mode = post_var('hub_mode');
  35                 $hub_callback = post_var('hub_callback');
  36                 $hub_verify_token = post_var('hub_verify_token');
  37                 $hub_secret = post_var('hub_secret');
  38                 $hub_topic = post_var('hub_topic');
  39
  40                 // check for valid hub_mode
  41                 if ($hub_mode === 'subscribe') {
  42                         $subscribe = 1;
  43                 } elseif ($hub_mode === 'unsubscribe') {
  44                         $subscribe = 0;
  45                 } else {
  46                         Logger::log("Invalid hub_mode=$hub_mode, ignoring.");
  47                         System::httpExit(404);
  48                 }
  49
  50                 Logger::log("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  51
  52                 if ($a->argc > 1) {
  53                         // Normally the url should now contain the nick name as last part of the url
  54                         $nick = $a->argv[1];
  55                 } else {
  56                         // Get the nick name from the topic as a fallback
  57                         $nick = $hub_topic;
  58                 }
  59                 // Extract nick name and strip any .atom extension
  60                 $nick = basename($nick, '.atom');
  61
  62                 if (!$nick) {
  63                         Logger::log('Bad hub_topic=$hub_topic, ignoring.');
  64                         System::httpExit(404);
  65                 }
  66
  67                 // fetch user from database given the nickname
  68                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  69                 $owner = DBA::selectFirst('user', ['uid', 'hidewall', 'nickname'], $condition);
  70                 if (!DBA::isResult($owner)) {
  71                         Logger::log('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  72                         System::httpExit(404);
  73                 }
  74
  75                 // abort if user's wall is supposed to be private
  76                 if ($owner['hidewall']) {
  77                         Logger::log('Local user ' . $nick . 'has chosen to hide wall, ignoring.');
  78                         System::httpExit(403);
  79                 }
  80
  81                 // get corresponding row from contact table
  82                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  83                         'pending' => false, 'self' => true];
  84                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  85                 if (!DBA::isResult($contact)) {
  86                         Logger::log('Self contact for user ' . $owner['uid'] . ' not found.');
  87                         System::httpExit(404);
  88                 }
  89
  90                 // sanity check that topic URLs are the same
  91                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
  92                 $self = System::baseUrl() . '/api/statuses/user_timeline/' . $owner['nickname'] . '.atom';
  93
  94                 if (!Strings::compareLink($hub_topic, $contact['poll']) && !Strings::compareLink($hub_topic2, $contact['poll']) && !Strings::compareLink($hub_topic, $self)) {
  95                         Logger::log('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
  96                         System::httpExit(404);
  97                 }
  98
  99                 // do subscriber verification according to the PuSH protocol
 100                 $hub_challenge = Strings::getRandomHex(40);
 101
 102                 $params = http_build_query([
 103                         'hub.mode' => $subscribe == 1 ? 'subscribe' : 'unsubscribe',
 104                         'hub.topic' => $hub_topic,
 105                         'hub.challenge' => $hub_challenge,
 106                         'hub.verify_token' => $hub_verify_token,
 107
 108                         // lease time is hard coded to one week (in seconds)
 109                         // we don't actually enforce the lease time because GNU
 110                         // Social/StatusNet doesn't honour it (yet)
 111                         'hub.lease_seconds' => 604800,
 112                 ]);
 113
 114                 $hub_callback = rtrim($hub_callback, ' ?&#');
 115                 $separator = parse_url($hub_callback, PHP_URL_QUERY) === null ? '?' : '&';
 116
 117                 $fetchResult = Network::fetchUrlFull($hub_callback . $separator . $params);
 118                 $body = $fetchResult->getBody();
 119                 $ret = $fetchResult->getReturnCode();
 120
 121                 // give up if the HTTP return code wasn't a success (2xx)
 122                 if ($ret < 200 || $ret > 299) {
 123                         Logger::log("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 124                         System::httpExit(404);
 125                 }
 126
 127                 // check that the correct hub_challenge code was echoed back
 128                 if (trim($body) !== $hub_challenge) {
 129                         Logger::log("Subscriber did not echo back hub.challenge, ignoring.");
 130                         Logger::log("\"$hub_challenge\" != \"".trim($body)."\"");
 131                         System::httpExit(404);
 132                 }
 133
 134                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 135
 136                 System::httpExit(202);
 137         }
 138         exit();
 139 }